A prospective study for evaluating the effect of gastric targeted biopsy sampling with I‐scan optical enhancement on the diagnostic yield of CLOtest for Helicobacter pylori infection

Abstract Background and Aim of the Work Helicobacter pylorigastritis can cause serious adverse effects in the short and long term. I‐scan optical enhancement (OE) has a potential role to distinguish areas of infected mucosa and allow for targeted biopsy. It improves visual contrast and mucosal pattern characterization. The work aims to determine if the diagnostic yield of the CLOtest could be improved by using endoscopic I‐scan OE technology for targeted gastric biopsy sampling. Patients and Methods A prospective study recruited 112 adult patients with active H. pylori infection diagnosed by C13 UBT at Nizwa General Hospital from March 2021 to January 2022. The patients underwent a careful examination by nonmagnifying upper endoscopy and I‐scan OE 3 moods, then randomly allocated into two groups. Group A: nontargeted double biopsies from the antrum and mid corpus. Group B: I‐scan OE‐directed targeted biopsy from abnormal mucosal patterns. The biopsy specimens were inoculated into CLOtest kits; the reading time of the positive results was at 1, 4, and 24 h. Results Group B had a 92.8% positive CLOtest compared to 89.3% in group A (p = 0.501). One‐hour CLOtest was positive in 78.5% of the patients in group B compared to 60.7% in group A (p = 0.047), while group A had a significantly more positive CLOtest at 24 h. Conclusion Sampling a targeted gastric biopsy with the aid of I‐scan ‐OE for CLOtest significantly hastens the positive reading time with high sensitivity.

pylori organisms by RUT. 18  topography. It can detect more subtle mucosal abnormalities, 17,20 and it is easy to observe and assess the abnormal mucosa with the aid of I-scan technology and gain more information from visual examination of the gastric mucosa than standard white light endoscopy (WLE). 18,19,21 The nonmagnifying I-scan exam provides better image quality of H. pylori gastritis. 22 It is superior to the WLE in identifying H. pylori infection-related abnormal endoscopic features with higher diagnostic accuracy. 23 Pentax's new endoscopic platform integrated the secondgeneration "I-scan optical enhancement" (OE). It incorporates an optical filter with improved visual contrast and provides extra information through improving vessel and mucosal pattern characterization. 17 The work aimed to determine if the diagnostic yield of CLOtest can be improved by using I-scan OE technology for targeted biopsy sampling from areas with endoscopic abnormal mucosal patterns associated with current H. pylori infection. The recruited patients were assessed clinically and biochemically, then examined by upper endoscopy, initially with HD-WLE (high definition WLE), followed by I-scan OE 3 moods successively. The patients were randomly distributed (before endoscopy) in a 1:1 ratio (sequentially numbered) into;

| PATIENTS AND METHODS
Group A (nontargeted, dual biopsy): included 56 patients; two samples were taken, one from the antrum on the greater curvature, approximately 3 cm from the pyloric ring, avoiding areas of ulceration and obvious IM, and one from normal-appearing corpus near midbody on the greater curvature. 9,11,12 The two samples were combined and placed into one test kit. 9 Group B (Targeted single biopsy by I-scan OE); After careful endoscopic exam and identification by I-scan OE, a single targeted biopsy was taken from either of the following gross or subtle abnormal mucosal patterns: (1) diffuse homogenous redness, (2) mucosal edema, (3) antral nodularity, (4) enlarged gastric fold, according to the following cascade: (1) overlapped abnormal mucosal patterns, (2) the most severe or prominent of nonoverlapped, coexistent patterns, (3) the most affected or severe part of a single pattern, (4) avoiding areas with suspected atrophic gastritis and IM with the aid of I-san OE.

| Gastroscopy protocol
All procedures were performed with PENTAX Medical EPK-i7010, IM: grayish-white and slightly elevated plaques with a villous appearance. It is surrounded by a mix of patchy pink and pale areas of the mucosa, forming an irregularly uneven surface ( Figure 5).

| Data analysis
The collected data were analyzed using SPSS (IBM SPSS Statistics 28.0). Mean, standard deviation (SD), and range was used for summarizing quantitative data, t-test was used for their analysis.
Number and percentages were used for summarizing qualitative data, while the normal Z-test was used to assess the significant difference between the two proportions. A p-value of < 0.05 was considered statistically significant. Table 1 shows the characteristics of the 112 patients recruited in the study [female 50, male 62, mean age 42.9 ± 14.5 (range: 17-69 years)]. There was no significant difference in the mean age of the patients between the groups. The most common indication for upper endoscopy was refractory reflux symptoms (35.7%), followed by epigastric pain (18.7%), dysphagia (10.7%), and dyspepsia (9.8%).
The single abnormal mucosal patterns were more prevalent than multiple (more than one) abnormal patterns either overlapped or isolated (70.5% vs. 29.5%, respectively), with no significant difference between the two groups (p = 0.98). The most common site for biopsy in group B (targeted) was the corpus (60.7%), followed by the antrum (28.6%), then the least was the fundus (10.7%). Table 2

| DISCUSSION
The CLOtest is a commonly used RUT for detecting H. pylori infection with high sensitivity; however, its false-negative results are still apparent. Missing a site rich in H. pylori organisms could be because the biopsy is randomly taken or taken from a normallooking mucosa in the corpus or incisura as recommended 11,12 instead of targeting the abnormal mucosal patterns correlated directly with H. pylori load and activity. 14 Furthermore, the early reading of the test result 3 is a postendoscopic cause of falsenegative. I-scan OE, which can better detect and enhance abnormal mucosal patterns than HD-WLE, 17 will aid to direct where the mucosa with viable and presumed high H. pylori load is present and overcome many causes of false-negative results. 23 The targeted biopsy sampling can lead to more CLOtest sensitivity, decrease false-negative results, and shorten the time to get positive readings. All of the previous will help in accurate and early decision-making for diagnosing and managing the H. pylori In this study, the single targeted biopsy-based CLOtest achieved a high sensitivity rate and overcame the previously mentioned sample error risk; however, there was no significant increase in the sensitivity over the nontargeted dual random biopsy-based CLOtest (92.8% vs. 89.3%). On the other side, multiple biopsies for CLOtest have a higher risk of being missed, slipped, or crushed, especially if taken by biopsy forceps simultaneously or during incubation in the CLOtest kit, with resultant false-negative results. The nontargeted dual biopsy in this study was taken separately and then combined outside before CLOtest incubation as recommended to increase sensitivity, 9 but this was time-consuming.
The sensitivity of CLOtest with a single random biopsy is widely affected by the severity of gastritis with atrophy. Lan et al. 10 reported a decrease in CLOtest sensitivity when the degree of gastritis with atrophy increased from moderate to severe (from 91% to 66%, respectively), and additional corpus biopsy resulted in only a 16.67% increase in the sensitivity. It is well known that gastric mucosal atrophy and IM are the leading causes for false-negative CLOtest.
Using I-scan OE in targeting specific abnormal mucosal patterns and avoiding suspected areas with atrophy and IM, especially in the antrum, helped to get such higher sensitivity from a single biopsy in this study. This agrees with Dohi et al., who reported that IEE technology had improved the visibility of endoscopic findings and the accuracy of endoscopic diagnosis of IM. 31 On the other side, Tahir et al. 3 reported that the absence of gastritis was associated with a slightly higher rate of false-negative CLOtest results, and the use of PPI contributed only to false-negative CLOtest in the absence of gastritis endoscopically. This highlights the importance and relationship between targeting gastritis-associated mucosal abnormalities and the sensitivity of CLOtest as in this study. All patients were positive for H. pylori by UBT; it was not possible to calculate specificity for the two groups as there were no patients without H.

| LIMITATIONS
Subjective evaluation of the severity of mucosal abnormalities and preference of one over another in sampling and inter-observational agreement is difficult to be standardized. It is limited to a single center.
The nonmagnifying I-scan technology, as magnifying I-scan, could detect more subtle mucosal abnormalities, especially in apparently looking normal mucosa.